Axial flow rotary engine

ABSTRACT

The disclosure is of an axial flow rotary internal combustion engine constructed in three sections, a compressor section, a combustion section and an expander section. The compressor section includes male and female rotors with complementary, single turn lobe and groove in which an air-fuel mixture is compressed and discharged from a port at the end of the groove as the port overtakes and traverses an arcuate intake port in the cylindrical combustion block, which is rotating at a slower speed. After the intake port is traversed and sealed off, an ignition port in the combustion chamber exposes a spark plug and the mixture is ignited. Substantially complete combustion takes place while the combustion chamber is sealed off and isolated. Then an entry port into the helical groove of female expander rotor overtakes and traverses an arcuate combustion chamber exhaust port and the combusted gases are discharged and expanded into the expander section. The expander section comprises a pair of complementary male and female rotors with complementary helical groove and lobe and are of a larger volume than the compressor rotors to enable full expansion. Power is taken off a shaft of one of the expander rotors.

RELATED APPLICATION

This application is a continuation of our co-pending application Ser.No. 07/079,704, filed July 30, 1987 for "Axial Flow Rotary Engine," nowabandoned.

BACKGROUND OF THE INVENTION

An internal combustion engine of the rotary type has a number ofadvantages over a conventional reciprocating engine. For example, therotary engine has substantially fewer moving parts; it does not have thedynamic balancing, vibration and inertia problems that occur inreciprocating engines, particularly at high speeds; and it has higherpower output capabilities per unit of weight.

PRIOR ART

British Pat. No. 889,246 granted to Hardy in 1962 shows a rotary enginewith compressor and turbine of the intermeshing screw type. However, thefixed combustion chamber is always in communication with the compressionand expansion rotors. This creates losses and excessive pressure on thecompressor. Further, the overall engine size is excessive because of thelengthy compression and expansion sections required.

In Schmidt U.S. Pat. No. 3,518,875 the combustion chamber is undesirablylong and narrow and there is no provision for seals or lubrication.Moreover, there is no efficient sealing of the combustion chamber.

In Nilsson U.S. Pat. No. 2,622,787, there is no suggestion as to how acombustion chamber might fit and the porting system employed does notlend itself to the low volume, sharply defined space required for apractical combustion chamber.

In Kraus U.S. Pat. No. 1,688,816, the combustion chamber is long andthin, extending from the central, transfer chamber through to thearcuate expansion chamber. The spark plug is actually positioned in theexpansion chamber, and the fuel charge is ignited as the transferchamber opens to the expansion chamber. In the elongated expansionchamber, combustion continues over an extended period.

Japanese Pat. No. 58-160515 (1983) and German Pat. No. DE 332-707A(1985) both show long, narrow combustion chambers which are of anineffecient shape, and they both show identical rotor profiles.

OBJECTS OF THE INVENTION

It is an object of this invention to provide an axial flow rotary enginethat is economical to manufacture and efficient in operation.

It is a further object of this invention to provide a rotary type, axialflow, internal combustion engine with means for effectively sealing offthe combustion chamber from both the compression chamber and theexpansion chamber.

It is a further object of this invention to provide a rotary type axialflow engine with a separate combustion chamber to provide complete andefficient combustion in advance of expansion.

It is a further object of this invention to provide a rotary type axialflow, internal combustion engine with a separate expansion chamber toensure complete expansion and utilization of the combusted gases.

It is a further object of this invention to provide a rotary type,positive displacement internal combustion engine that has few movingparts.

It is a further object of this invention to provide an axial flowinternal combustion engine that converts more thermal energy tomechanical energy.

It is a further object of this invention to provide an axial flowinternal combustion engine that has intake, compression, combustion,power and exhaust stages in a single housing.

It is a further object of this invention to provide for more completecombustion in an axial flow rotary engine so as to achieve reducedpolution and increased efficiency.

It is a further object of this invention to provide an axial flow rotaryengine with a combustion chamber configuration that minimizes anytendency to foster premature ignition of gases.

It is a further object of this invention to provide an axial flow,rotary type engine that is compact in construction.

Other objects and advantages of this invention will become apparent fromthe description to follow, particularly when read in conjunction withthe accompanying drawing.

SUMMARY OF THE INVENTION

In the rotary engine of this invention, there are an axial flow rotarycompressor section, a multi-chambered, rotating combustion section andan axial flow rotary expansion section, all placed in tandem within asingle housing. Valving is accomplished through ports in the mating,circular ends of the rotors, utilizing their differential speeds to openand close ports by bringing them into and out of alignment. Thecompressor section comprises a pair of male and female screw-type rotorsmounted for rotation about parallel axes. The compressor rotors havecylindrical bodies of equal diameter, there being a single-turn helicalgroove formed in and around the cylindrical body of the female rotor.Compressed gases are discharged through a passageway which extends fromthe end of the helical groove to open in a discharge port in thecircular end wall of the female rotor, and as the discharge portovertakes and passes along an arcuate port in an engaging circular endwall of a slower turning combustion chamber housing, the gases aretransferred. Then when the female compressor rotor rotates further aheadof the combustion housing to close off the entry port into thecombustion chamber, the compressed gases are ignited. After completecombustion within the sealed chamber, the combusted gases are dischargedthrough a combustion chamber exhaust port, as an intake port in thecircular end of the mating female rotor of the expansion sectionovertakes it and rotates past.

The expansion section also comprises a pair of male and femalescrew-type rotors, basically with cylindrical bodies of equal diameter,having complementary, single-turn helical lobes and grooves. Theexpander rotors are of larger diameters and/or lengths then those of thecompressor section to provide greater volume for more complete expansionof the hot combusted gases. A portion of the output from the engine isemployed through suitable gearing to drive the compressor rotors.

BRIEF DESCRIPTION OF THE DRAWING

In the drawing:

FIG. 1 is a horizontal section view taken through an axial flow rotaryengine embodying features of this invention;

FIG. 2 is a vertical section view taken along line 2--2 of FIG. 1;

FIG. 3 is a partial vertical section view taken along line 3--3 of FIG.1; and

FIG. 4 is a partial vertical section view taken along line 4--4 of FIG.1.

DESCRIPTION OF A PREFERRED EMBODIMENT

Referring now to the drawing with greater particularity, the axial flowrotary engine 10 of this invention preferably comprises a single housing12 formed with a compressor section 14, a combustion section 16 and anexpansion or turbine section 18. The housing 12 is provided with coolingjackets 19 for circulation of cooling water around all three sections14, 16 and 18.

The output of the rotary engine is delivered at power shaft 20, which isrotatably mounted in suitable bearings 22 and 24 in the expander section18. A power takeoff, rearward extension 26 of the output shaft 20 isfurther rotatably mounted at 27 and employed to drive the compressorunit 14.

The Compression Section

Specifically, a gear 28 on the power takeoff shaft 26 drives a gear 29,which is rotatably mounted on the input shaft 30 of the femalecompressor rotor 31. The input shaft 30 carries a rotatably mountedtiming gear 32 meshing with a complementary timing gear 34 keyed at 34ato the shaft 36 of the male compressor rotor 40, so that both rotorshafts 30 and 36 rotate at the same speed. The compressor rotor inputshafts 30 and 36 are journalled in bearings 42 and 44 in the housing 12.

The female and male compressor rotors 31 and 40 have basicallycylindrical bodies 46 and 48, which are of the same diameter, rotatingon parallel axes in tangential sealing engagement along contact line 50.The male rotor 40 preferably has a single turn helical lobe 52 of onecomplete turn and the female rotor 31 has a single turn, complementarygroove 54. The helical groove 54 terminates short of the downstream end56 of the female rotor 31 to form a circular end plate through which acompressor exit port 55 extends to open through the circular end 56 ofthe cylindrical female rotor body 46.

As shown in FIG. 2, the compression section chamber housing 12 forms apair of intersecting internal cylinders 58 and 60, with the smallerupper cylinder 58 snugly receiving the female rotor 31 and the largerlower cylindrical 60 snugly receiving the helical lobe 52 around themale rotor 40. The overall radius of the lobe is slightly less than √3r,where r equals the radius of the basic cylindrical rotor bodies 46 and48. These proportions cause a spring mounted wiper seal 53 in the tip ofthe lobe 52 to pass one cusp 54b of the female rotor 31 at the sameinstant that the other cusp 54a is just making contact with the basiccylindrical surface 48 of the male rotor 40. Thus, at all times aminimum of two sealing lines are provided, one seal moving around thegroove or recess 54 from cusp 54a to cusp 54b and then around theinterior surface of the cylindrical chamber 60; and the other seal 50achieved at the tangential line contact 50, which is substantiallystationary.

The continuous seal maintained by pressing the leading surface 52a ofthe lobe 52 against the downstream cusp 54b of the female rotor 31 isachieved by spring loading the compressor rotor timing gears 32 and 34.As shown in FIGS. 1 and 4, a carrier ring 61 for the input gear 29 iskeyed at 62 to the female rotor shaft 30 and the associated timing gear36 is rotatable thereon. Compression springs 63 are mounted between thecarrier ring 61 and the timing gear 32 to bias the timing gear 32, andhence, the mating timing gear 34 in a forward direction. Any resistanceto turning may be absorbed by the compression springs 63. The gears 29and 32 are keyed together at 32a by an extension of gear teeth. Thegears 29 and 32 may be set to yieldably press the lobe 52 of the malecompressor rotor 40 against the downstream cusp of the female rotor 31.In addition, the spring 63 will compensate for wear on the tooth or lobe52.

The wiper seal 53 is slidably carried in a slot that extends along theouter tip of the helical lobe 52, and is spring mounted so as to bebiased against the inner surface 54a to 54b of the female groove 54 andthen against and around the cylindrical surface 60 of the compressorchamber. The wiper ring 53 is of a low density, low friction material soas to minimize centrifugal forces and heat of friction, and is heatresistant for high temperature operation. A suitable material isgraphite-fluorocarbon. Similar wiper seals 53 are provided on both thecompressor and expander sections 14 and 18.

In operation, the compressor rotors 31 and 40 are in continuous rotationwith an air-fuel mixture being drawn in through an intake port 66 to theintake space 68 and then between the compressor section rotors 31 and 40where the air-fuel mixture is forced downstream and compressed betweenthe lobe 52 and the walls of the groove 54, finally being forced throughthe exit port 55 opening from the end of the helical groove 54 and theotherwise solid circular wall 56 of the female rotor 31.

The Combustion Section

The combustion section 16 comprises a generally cylindrical, body orblock 70 rotatably mounted in a complementary cylindrical chamber 71,which is formed in the housing 12 between the compression and expansionsections 14 and 18. The combustion chamber block 70 has twosemi-cylindrical combustion chambers 72a and 72b, each with an arcuateintake port 74a and 74b and an arcuate exhaust port 76a and 76b. Theintake and exhaust ports 74 and 76 are normally closed by snug sealingengagement of the circular end walls of the combustion chamber block 70with the circular end walls 56 and 78 of the female compressor rotor 31and the female expander rotor 80 to be further described. A pinion 82 onthe male compressor rotor shaft 84 drives a gear 86 on the cylindricalcombustion block 70 to rotate the combustion block or housing 70 atone-half the speed of the compressor rotors 31 and 40, (also at one-halfthe speed of the expander rotors 80 and 94 to be described) so thatduring successive revolutions of the compressor rotors, the compressedair-gas mixture is delivered to alternate chambers 72a and 72b of thecombustion unit 16.

A spark plug 88 is mounted in the housing 12 and a spark port 90a or 90bin each combustion chamber 72a and 72b aligns with the spark plug at theappropriate instant for ignition. After combustion, the arcuate exhaustport 76a or 76b of the combustion chamber remains closed for a period toensure complete combustion, and then the fully combusted gases areevacuated as the entry port 92 into the female expander rotor 80overtakes the exhaust port 76a or 76b and overtakes the exhaust port 76aor 76b and rotates past.

The Expansion Chamber

The expansion or turbine section 18 is very similar in construction tothe compressor 14 but with a larger total volume, in the order of twicethe compressor volume to allow for more complete expansion of the hotcombusted gases within the engine 10. The female expander rotor 80 iscoaxial with the female compressor 31, and the male expander rotor 94 ispreferably disposed 180° from the axis of the male compressor rotor 31so as to time properly with the combustion chamber exhaust ports 76a and76b. Spring-biased wiper seals 96 are mounted in the lobe 98 of the maleexpander, as in the compressor rotor, and in driving, the upstream cuspof the female rotor is maintained in contact with the trailing face ofthe male rotor lobe 98. This sealing relationship is maintained byspring loading the output timing gears 99 and 100.

Specifically, the one timing gear 99 is keyed at 102 to the female rotorshaft 104 while the other timing gear 100 is rotatably carried on themale rotor shaft 20, i.e. the output shaft. Keyed at 106 on the outputshaft 20 is a support ring 108 and a series of compression springs 110yieldably bias the timing gear 100 in a direction to maintain sealingcontact between the expander lobe 98 and groove 94a.

Operation

As the male and female compressor rotors 31 and 40 rotate about parallelaxes they draw in from the intake chambers 68 a fuel-gas-air mixture (orjust air in case of diesel operation) and, when the lobe 52 moves aroundcylindrical chamber wall 60 and into sealing engagement with the wall ofthe groove 54 of the female rotor 31, the air-fuel mixture is trappedand forced toward the right in FIG. 1 and compressed against thedownstream end 56 of the compression section 14.

In the meantime, the combustion unit cylindrical block 70 is beingrotated by engagement of the gears 82 and 86, in the same direction ofrotation as that of the female rotor 40 though at one-half the speed. Ata fixed time, the compressor transfer port 55 overtakes the arcuateentry port 74a of the combustion chamber 72a and, as the two continue torotate in the same direction, the transfer port 55 traverses the arcuatecombustion entry port 74a. When the compressor transfer port 55 passesthe arcuate port 74a and is opposed by the imperforate upstream surfaceof the cylindrical combustion unit 70, the combustion chamber 72a issealed off. Then, at a predetermined time, the ignition port 90a of theupper combustion chamber 72a moves into alignment with the spark plug 88and the spark ignites the compressed gas-fuel mixture.

In an alternative embodiment for diesel operation, air alone could becompressed in the compressor section and introduced through an alignedport 74a or 74b into a combustion chamber 72a or 72b. Then, during aprecisely defined period, diesel fuel is injected through port 90a andignited by heat of compression.

In the meantime, the female expander rotor 80 is also rotating coaxiallywith, and in the same direction as, the combustion unit block 70 and, ata predetermined time in its rotation, the expander entry port 92overtakes and traverses the arcuate combustion chamber exhaust port 76a,which is now in the position of the lower combustion chamber. Thecombusted gases expand rapidly into the expander section 18 to drive thehelical lobe 98 before it and impel the expander rotors 80 and 94 topower the output shaft 20.

At the same time, the initially lower combustion chamber 72b has movedto the position of the upper combustion chamber and a compressedair-fuel mixture (or air alone in the case of diesel operation) isdelivered to the upper combustion chamber as the lower combustionchamber is delivering its combusted gases for expansion in the expanderchamber 18.

In the preferred embodiment shown, the combustion unit contains twocombustion chambers 72a and 72b and is driven at one-half the speed ofthe compressor rotors 31 and 40, as well as the driven expander rotors80 and 94. However, the cylindrical combustion chamber block 70 couldcontain three or even four combustion chambers 72. In that case, sinceonly one combustion chamber entry port 74 should be exposed during eachrotation of the female compressor rotor 31, and likewise one exhaustport 76 exposed during each rotation of the female expander rotor 80,the combustion unit block 70 would be rotated at two-thirds orthree-fourths of the speed of the main rotors 31 and 80, depending onwhether there were three or four combustion chambers 72. Each combustionchamber is charged during one revolution of the compressor and expanderfemale rotors 31 and 80 and discharged during the next revolution.Hence, with three combustion chambers, each chamber is inactive, i.e.remains void for dissipation of heat, during the third revolution of themain rotors and with four chambers, each is inactive during the thirdand fourth revolutions.

The provision of additional combustion chambers would enable the enginedesigner to allow for longer dwell periods before and/or after ignitionand would, therefore, allow for greater rotational speed of the engine.In addition, one could allow more time for the possible transfer of heatfrom the combustion chamber wall to the compressed fuel-air mixtureprior to ignition.

Assuming arbitrarily that zero degrees occurs where the lobe 52 and thehelical groove 54 at the downstream end of the compressor rotors 31 and40 are aligned, as shown in FIG. 2, the sequence of operation may be asfollows:

    ______________________________________                                        Event             Timing      Period                                          ______________________________________                                        Injection and compression                                                                       -285° to +15°                                                               300°                                     Dwell             +15° to 20°                                                                  5°                                      Ignition          20°                                                  Combustion        20° to 80°                                                                   60°                                     Expansion and exhaust                                                                            80° to 430°                                                                350°                                     Dwell             430° to 435°                                                                 5°                                      Total                         720°                                     Two full revolutions                                                          ______________________________________                                    

This describes a spark-ignited engine, but the engine 10 of ourinvention could readily be adapted for diesel operation, with a fuelinjector replacing the spark plug 88. In such operation one wouldprovide for a period of fuel injection.

This invention has been described with compressor and expander sections14 and 18 comprising basically cylindrical bodies, one with a singlehelical lobe and the other with a complementary, single helical groove.However, it is to be understood that the invention covers as well,multiple lobes and complementary grooves, with the rotational speed ofthe rotors adjusted accordingly. Similarly, while the rotors have beendescribed as complementary male and female rotors, features of theinvention are applicable as well to identical, meshing rotors.

Lubrication

Since the expander 18 receives only fully combusted gases and such gasesare at pressures of up to 1,000 psi, lubrication must entail a systemother than conventional low pressure recirculating oil systems, orinjection with the fuel charge.

Accordingly, oil is pumped under high pressure (say 1,000 psi) and verylow volume into an oil gallery 120 (FIG. 2), which is bored axially inthe cylinder wall 12 adjacent to the entry edge of the female rotor.Very small holes 122 are drilled between the gallery 120 and thecylinder internal surface 58 at appropriate intervals. A rod or shaft124 with a small helical groove or passageway 126 turned around itsperiphery is snugly received within the oil gallery 120 and is driven intime with the female rotor 31 so that oil is injected between the femalerotor 33 and its accommodating cylinder wall 58 just after the adjacentportion of the female groove or cavity 54 passes the oil hole 122. Therod 124 may be rotated by suitable intermediate gearing (not shown) fromthe gear 128 (FIG. 1) on the female rotor shaft 30. The timing may beset so that a small quantity of oil is injected at each rotation or at agiven multiple of each rotation, depending on the lubricationrequirements.

The oil deposited on the female rotor wall 58 tends to collect at thecusp 54a where the wiper 53 on the end of the lobe 52 can pick it up andfurther distribute the lubrication. Further, the trailing cusp 54blikewise distributes oil over the leading face 52a of the lobe 52 bymeans of its contact with the leading face.

The high pressure oil system lubricates both the compressor and theexpander in the manner described above. For example, a similar rod withhelical groove may be rotated by a gear 130 on the female expander rotorshaft 104. The same high pressure system likewise feeds the entire outersurface of the combustion chamber, with timed pulses coming from one orboth of the oil galleries.

While this invention has been described in conjunction with preferredembodiments thereof, it is obvious that other modifications and changestherein may be made by those skilled in the art to which it pertainswithout departing from the spirit and scope of this invention, asdefined by the claims appended hereto.

What is claimed as invention is:
 1. An internal combustion enginecomprising:a housing having an intake port at one end thereof and anexhaust port at the other end thereof; a compression chamber in saidhousing near said one end; compressor means in said compression chamber;said compressor means including a downstream compressor outlet wallrotating in said compression chamber; a compressor transfer port openingthrough said downstream outlet wall; an expansion chamber in saidhousing near said other end thereof to receive combusted gases; workmeans in said expansion chamber driven by expanding, combusted gases;said work means including an upstream expander inlet wall rotating insaid expansion chamber; means rotating said compressor outlet wall atthe same rotational drive speed as said expander inlet wall; anexpansion chamber inlet port opening extending through said upstreaminlet wall; a cylindrical combustion chamber block rotatable in saidhousing intermediate said compression chamber and said expansionchamber; said combustion chamber block having upstream and downstreamend walls in face to face sealing engagement with said compressor outletand expander inlet walls; at least two combustion chambers in saidblock, substantially equally spaced around said block, each with aninlet port through said upstream wall to receive a charge of compressedgas from said compressor transfer port and a discharge port through saiddownstream wall to release combusted gases through said expansionchamber inlet port; means rotating said block at a reduced speedrelative to the speed of rotation of said compressor outlet wall andsaid expander inlet wall so that said compressor transfer port isaligned with and in communication with one of said combustion chamberinlet ports during a first portion of each revolution of said combustionchamber block, said combustion chamber inlet and discharge ports beingclosed off by said compression outlet wall and said expander inlet wall,respectively, during an intermediate portion of each revolution of saidcombustion chamber block and said expander inlet port is aligned withand in communication with said one combustion chamber discharge portduring a third portion of each revolution of said combustion chamberblock; and means for igniting said charge of compressed gas during saidintermediate portion of each revolution of said combustion chamberblock; said combustion chambers being substantially hemispherical; thespeed of rotation of said compressor outlet wall is in the same ratio tothe speed of rotation of said combustion chamber block as the number ofcombustion chambers in said block is to said number of combustionchambers less one.
 2. The internal combustion engine defined by claim 1wherein:said combustion chamber inlet and discharge ports and saidcompressor transfer and expander inlet ports are shaped and positionedto shut off said one combustion chamber from both said compressionchamber and said expansion chamber during a combustion period occuringthrough an angle of rotation of said combustion chamber block of atleast 15°.
 3. The internal combustion chamber defined by claim 2wherein:said combustion chamber inlet and discharge ports extend alongarcs transversed by said compressor transfer port and said expanderinlet port, respectively.
 4. The internal combustion engine defined byclaim 1 wherein:each of said combustion chambers is shorter axially thansaid expansion chamber.
 5. The internal combustion engine defined byclaim 1 wherein said compressor means comprise:a pair of male and femalecompressor rotors mounted in said compression chamber for rotation aboutparallel axes; said compressor rotors having cylindrical bodies; saidmale compressor rotor having a helical lobe formed around and along itscylindrical body from end to end thereof; and said female compressorrotor having an oppositely directed complementary, helical groove in andaround its cylindrical body receiving said helical lobe during rotationof said rotors in opposite directions.
 6. An internal combustion enginecomprising:a housing having an intake port at one end thereof and anexhaust port at the other end thereof; a compression chamber in saidhousing near said one end; compressor means in said compression chamber;said compressor means including a downstream compressor outlet wallrotating in said compression chamber; a compressor transfer port openingthrough said downstream outlet wall; a pair of male and femalecompressor rotors mounted in said compression chamber for rotation aboutparallel axes; said compressor rotors having tangentially engagingcylindrical bodies; said male compressor rotor having a single turnhelical lobe formed around and along its cylindrical body from end toend thereof; said female compressor rotor having an oppositely directedcomplementary, single turn helical groove in and around its cylindricalbody receiving said helical lobe during rotation of said rotors inopposite directions; the cylindrical body of said female compressorrotor being longer than said male compressor rotor so that there is anuninterrupted cylindrical portion with a circular end surface at thedownstream end of said female rotor forming said compressor outlet wall;an expansion chamber in said housing near said other end thereof toreceive combusted gases; work means in said expansion chamber driven byexpanding, combusted gases; said work means including an upstreamexpander inlet wall rotating in said expansion chamber; means rotatingsaid compressor outlet wall at the same rotational speed as saidexpander inlet wall; an expansion chamber inlet port opening extendingthrough said upstream inlet wall; a cylindrical combustion chamber blockrotatable in said housing intermediate said compression chamber and saidexpansion chamber; said combustion chamber block having upstream anddownstream end walls in face to face sealing engagement with saidcompressor outlet and expander inlet walls; at least two combustionchambers in said block, substantially equally spaced around said block,each with an inlet port through said upstream wall to receive a chargeof compressed gas from said compressor transfer port and a dischargeport through said downstream wall to release combusted gases throughsaid expansion chamber inlet port; means rotating said block at areduced speed relative to the speed of rotation of said compressoroutlet wall and said expander inlet wall so that said compressortransfer port is aligned with and in communication with one of saidcombustion chamber inlet ports during a first portion of each revolutionof said combustion chamber block, said combustion chamber inlet anddischarge ports being closed off by said compression outlet wall andsaid expander inlet wall, respectively, during an intermediate portionof each revolution of said combustion chamber block and said expanderinlet port is aligned with and in communication with said one combustionchamber discharge port during a third portion of each revolution of saidcombustion chamber block; and means for igniting said charge ofcompressed gas during said intermediate portion of each revolution ofsaid combustion chamber block.
 7. The internal combustion engine definedby claim 6 wherein:said combustion chamber inlet and discharge ports andsaid compressor transfer and expander inlet ports are shaped andpositioned to shut off said one combustion chamber from both saidcompression chamber and said expansion chamber during a combustionperiod occuring through an angle of rotation of said combustion chamberblock of at least 15°.
 8. The internal combustion chamber defined byclaim 7 wherein:said combustion chamber inlet and discharge ports extendalong arcs traversed by said compressor transfer port and said expanderinlet port, respectively.
 9. The internal combustion engine defined byclaim 6 wherein:each of said combustion chambers is shorter axially thansaid expansion chamber.
 10. The internal combustion engine defined byclaim 6 wherein:said combustion chambers are substantiallyhemispherical; means rotating said combustion chamber block so that saiddrive speed is in the same ratio to the rotary speed of said combustionchamber block as the number of combustion chambers in said block is tosaid number of combustion chambers less one.
 11. An internal combustionengine comprising:a housing having an intake port at one end thereof andan exhaust port at the other end thereof; a compression chamber in saidhousing near said one end; compressor means in said compression chamber;said compressor means including a downstream compressor outlet wallrotating in said compression chamber; a compressor transfer port openingthrough said downstream outlet wall; an expansion chamber in saidhousing near said other end thereof to receive combusted gases; workmeans in said expansion chamber driven by expanding, combusted gases;said work means including an upstream expander inlet wall rotating insaid expansion chamber; means rotating said compressor outlet wall atthe same rotational speed as said expander inlet wall; an expansionchamber inlet port opening extending through said upstream inlet wall; acylindrical combustion chamber block rotatable in said housingintermediate said compression chamber and said expansion chamber; saidcombustion chamber block having upstream and downstream end walls inface to face sealing engagement with said compressor outlet and expanderinlet walls; at least two combustion chambers in said block,substantially equally spaced around said block, each with an inlet portthrough said upstream wall to receive a charge of compressed gas fromsaid compressor transfer port and a discharge port through saiddownstream wall to release combusted gases through said expansionchamber inlet port; means rotating said block at a reduced speedrelative to the speed of rotation of said compressor outlet wall andsaid expander inlet wall so that said compressor transfer port isaligned with and in communication with one of said combustion chamberinlet ports during a first portion of each revolution of said combustionchamber block, said combustion chamber inlet and discharge ports beingclosed off by said compression outlet wall and said expander inlet wall,respectively, during an intermediate portion of each revolution of saidcombustion chamber block and said expander inlet port is aligned withand in communication with said one combustion chamber discharge portduring a third portion of each revolution of said combustion chamberblock; and means for igniting said charge of compressed gas during saidintermediate portion of each revolution of said combustion chamberblock; said work means comprising: a pair of male and female expansionrotors mounted in said expansion chamber for rotation about parallelaxes; said expansion rotors having tangentially engaging cylindricalbodies; said male expansion rotor having a single turn helical lobeformed around and along its cylindrical body; said female expansionrotor having an oppositely directed complementary, single turn helicalexpansion groove in and around its cylindrical body receiving saidhelical lobe during rotation of said expansion rotors in oppositedirections; said female expansion rotor being longer than said maleexpansion rotor so that there is an uninterrupted cylindrical portionwith a circular end surface at the upstream end of said female expansionrotor forming said expander inlet wall; and said expansion chamberhaving a first cylindrical portion closely but rotatably receiving saidfemale expansion rotor and a second cylindrical portion closely butrotatably receiving said male expansion rotor with helical lobe.
 12. Theinternal combustion engine defined by claim 11 wherein:said combustionchamber inlet and discharge ports and said compressor transfer andexpander inlet ports are shaped and positioned to shut off said onecombustion chamber from both said compression chamber and said expansionchamber during a combustion period occuring through an angle of rotationof said combustion chamber block of at least 15°.
 13. The internalcombustion chamber defined by claim 12 wherein:said combustion chamberinlet and discharge ports extend along arcs traversed by said compressortransfer port and said expander inlet port, respectively.
 14. Theinternal combustion engine defined by claim 11 wherein:each of saidcombustion chambers is shorter axially than said expansion chamber. 15.The internal combustion engine defined by claim 11 wherein:saidcombustion chambers are substantially hemispherical; means rotating saidcombustion chamber block so that said drive speed is in the same ratioto the rotary speed of said combustion chamber block as the number ofcombustion chambers in said block is to said number of combustionchambers less one.
 16. An internal combustion engine comprising:ahousing having an intake port at one end thereof and an exhaust port atthe other end thereof; a compression chamber in said housing near saidone end; a pair of compressor rotors mounted for rotation in saidcompression chamber; one of said compressor rotors having a helical lobeformed around and along its body; the other of said compressor rotorshaving an oppositely directed complementary, helical groove in andaround its body receiving said helical lobe during rotation of saidrotors in opposite directions; said helical groove terminating short ofthe downstream end of said other rotor to form a compressor outlet wall;a compressor transfer port opening through said compressor outlet wall;an expansion chamber in said housing near said other end thereof toreceive combusted gases; a pair of expansion rotors mounted for rotationin said expansion chamber; one of said expansion rotors having a helicallobe formed around and along its body; the other of said expansionrotors having an oppositely directed complementary, helical expansiongroove in and around its body receiving said helical lobe duringrotation of said expansion rotors in opposite directions; said otherexpansion rotor being longer than said one expansion rotor so that thereis a circular end surface at the upstream end of said other expansionrotor forming an upstream expander inlet wall; an expansion chamberinlet port opening extending through said upstream inlet wall; meansrotating said compressor rotors at the same rotational speed as saidexpansion rotors; a combustion chamber block rotatable in said housingintermediate said compression chamber and said expansion chamber; saidcombustion chamber block having upstream and downstream end walls inface to face sealing engagement with said compressor outlet and expanderinlet walls; said combustion chamber block and said other compressionand expansion rotors all being in axial alignment; at least twocombustion chambers in said block, substantially equally spaced aroundsaid block, each with an inlet port through said upstream wall toreceive a charge of compressed gas from said compressor transfer portand a discharge port through said downstream wall to release combustedgases through said expansion chamber inlet port; means rotating saidblock at a reduced speed relative to the speed of rotation of said otherrotors so that said compressor transfer port overtakes and traverses incommunication with one of said combustion chamber inlet ports during afirst revolution of said rotors, and said expander inlet port overtakesand traverses in communication with said one combustion chamberdischarge port during a second revolution of said rotors, said onecombustion chamber inlet and discharge ports being closed off by saidcompression outlet wall and said expander inlet wall, respectively,during a combustion period between such traversing movements; and meansfor igniting said charge of compressed gas during said combustionperiod.